Effect of Hevea brasiliensis seed meal or Euphorbia heterophylla seed supplemented diets on performance, physicochemical and sensory properties of eggs, and egg yolk fatty acid profile in guinea fowl (Numida meleagris).

A total of 144 French selected breed (Galor) female guinea fowl (GF) of 42 wk of age were enrolled for a feeding trial of 15, 30, and 45 D duration. The birds were randomly assigned to 18 cages, each containing 8 birds. A total of 3 isonitrogenous and isocaloric dietary treatments were trialed, each diet comprising 6 replications (cages), which meant a total of 48 birds per diet. The GF were fed either a control diet C (commercial diet "FACI ponte 20", SIPRA, Ivory Coast, usually used for all poultry species) or the diet C supplemented with 5% Euphorbia heterophylla seeds (diet E) and the diet C supplemented with 5% Hevea seed meal (Hevea brasiliensis) (diet H). Animal performance were assessed for 3 periods (days 0 to 15, 0 to 30, and 0 to 45), and egg quality and composition were assessed at 15, 30, and 45 D of the trial. The results indicated no mortality during the trial. The laying rate was the highest (43.9%) with diet E and the lowest with diet C (32.5%), the laying rate with diet H being intermediate (38.5%). Diet E containing Euphorbia seeds led to a reduced cholesterol content of the eggs. Additionally, inclusion of Euphorbia seeds and, to a lesser extent, of the Hevea seed meal in the diet led to n-3 polyunsaturated fatty acid enriched GF eggs, with thereby, improved nutritional value. A sensory test did not find any difference between the 3 diets on trial.

Sedimentation field-flow-fractionation: emergence of a new cell separation methodology.

Field flow fractionation (FFF) methods were conceptualised in the late 1960s by J.C Giddings. These techniques are particularly suited for the retention and separation of micron and sub-micron sized particles. Systematic technological development as well as methodological procedures were established to achieve separations over the last 30 years. The elution mechanism of micron sized species is now known as 'steric/hyperlayer'. Cells are micron sized particles of life science interest, in particular those living in suspension. The separation of cells according to differences in their biophysical characteristics is therefore possible using the FFF principle. In the first part of this report, characteristics of classical cell separation methodologies are recounted as well as the specific features of FFF. In the second part, a review of cell separations or purifications obtained with sedimentation FFF techniques is given and FFF trends in cell separation is developed.

Osmolarity effects on red blood cell elution in sedimentation field-flow fractionation.

Field-flow fractionation (FFF) is an analytical technique particularly suitable for the separation, isolation, and characterization of macromolecules and micrometer- or submicrometer-sized particles. This chromatographic-like methodology can modulate the retention of micron-sized species according to an elution mode described to date as "steric hyperlayer". In such a model, differences in sample species size, density, or other physical parameters make particle selective elution possible depending on the configuration and the operating conditions of the FFF system. Elution characteristics of micron-sized particles of biological origin, such as cells, can be modified using media and carrier phases of different osmolarities. In these media, a cells average size, density, and shape are modified. Therefore, systematic studies of a single reference cell population, red blood cells (RBCs), are performed with 2 sedimentation FFF systems using either gravity (GrFFF) or a centrifugational field (SdFFF). However, in all cases, normal erythrocyte in isotonic suspension elutes as a single peak when fractionated in these systems. With carrier phases of different osmolarities, FFF elution characteristics of RBCs are modified. Retention modifications are qualitatively consistent with the "steric-hyperlayer" model. Such systematic studies confirm the key role of size, density, and shape in the elution mode of RBCs in sedimentation FFF for living, micronsized biological species. Using polymers as an analogy, the RBC population is described as highly "polydisperse". However, this definition must be reconsidered depending on the parameters under concern, leading to a matricial concept: multipolydispersity. It is observed that multipolydispersity modifications of a given RBC population are qualitatively correlated to the eluted sample band width.

Sedimentation field-flow fractionation application to Toxoplasma gondii separation and purification.

Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii, an intracellular protozoa of micronic size range (4-10 microm). Its classical purification processes are complex and often associated with low recovery. All investigation procedures concerning this parasite require its isolation and purification from at least the mouse ascitic fluid. For this purpose, a recently developed laboratory technology was used, i.e. sedimentation field-flow fractionation. This chromatographic-like separation technology was demonstrated to be particularly selective for isolation and separation of micron-sized biological particles. Sedimentation field-flow fractionation operated on the steric-hyperlayer mode was used to isolate the parasite from the remanent ascitic contaminants of different origins and from red blood cells. With this technology, 86% recovery with 97% viability was obtained in less than 30 min.